Track link with replaceable rail

ABSTRACT

A track link for an endless track chain assembly has a replaceable rail secured to one edge for engaging track rollers on a track suspension. The rail is welded to the link along its central portion and at its extreme ends. Intermediate the central portion and the ends of the rail, the rail is free to move longitudinally or &#39;&#39;&#39;&#39;grow&#39;&#39;&#39;&#39; with respect to the track link. In an alternative embodiment, the rail has its central portion bolted to the track link. A groove and key arrangement in the abutting surface of the rail and track link allow longitudinal growth of the rail while resisting lateral deflection forces.

llnited States Patent [1 1 Rugs et al.

[111 @{WEAM Matzfi, 1974 TRACK LINK WITH REPLACEABLE RAIL [75] Inventors: Roger L. Boggs, East Peoria; Harold L. Reinsma, Dunlap, both of I11.

[73] Assignee: Caterpillar Tractor (10., Peoria, Ill.

[22] Filed: Jan. 110, 1972 [21] App]. No; 216,611

6/1954 Great Britain 305/56 Primary Examiner-Richard J. Johnson Attorney, Agent, or FirmFryer, Tjensvold, Phillips & Lempio [5 7 I ABSTRACT A track link for an endless track chain assembly has a replaceable rail secured to one edge for engaging track rollers on a track suspension. The rail is welded to the link along its central portion and at its extreme ends. Intermediate the central portion and the ends of the rail, the rail is free to move longitudinally or grow with respect to the track link.

In an; alternative embodiment, the rail has its central portion bolted to the track link. A groove and key arrangement in the abutting surface of the rail and track link allow longitudinal growth of the rail while resisting lateral deflection forces.

5 Claims, 10 Drawing Figures PATENIEMR SIBM 3, 795A31 sum 1 or 3 IAR T) TRACK LINK WITH REPLACEABLE RAIL BACKGROUND OF THE INVENTION This invention relates to the'field of replaceable rail wear plates for track links. In the past, efforts to provide track links with replaceable rail wear plates have proved impractical. The major problem with such designs has been that the profile of the track links was not of sufficient height to allow for providing a replaceable portion of adequate thickness and strength.

Other problems experienced with prior art devises have related to providing a simple means of attaching the replaceable rails to the track links in a manner that provides lateral rigidity in the rails with respect to the track link while allowing them to grow longitudinally under the influence of repeated pounding of the track rollers.

SUMMARY OF THE INVENTION It is thus an object of the present invention to provide a track chain assembly which includes replaceable rails of sufficient thickness for adequate strength, on a track link also having sufficient thickness for adequate strength, in a track chain having a normal overall height.

It is a further object of this invention to provide a means for securing replaceable rails to track links in a manner that provides for lateral rigidity of the rails with respect to the track links, and allows longitudinal growing of the rail ends.

It is still another object of this invention to provide such a replaceable rail arrangement which will also allow simple replacement of the rails when they become WOI'II.

BRIEF DESCRIPTION OF THE DRAWINGS In the Drawings:

FIG. I is an elevational view of a portion of a track chain assembly for a crawler vehicle engaged by the vehicle drive sprocket.

FIG. 2 is a plan view of a section of the track chain assembly shown in FIG. 1.

FIG. 3 is a plan view of a section of a prior art track chain assembly.

FIG. 4 is a sectional view of a track joint of the prior art track chain shown in FIG. 3.

FIG. 5 is a sectional view of a track joint of the present invention.

FIG. 6 is a side view of a track link constructed in accordance with the present invention.

FIG. 7 is a sectional view of a track link taken along the line VIIVII in FIG. 6.

FIG. 8 is a side view of a portion ofa track link illustrating another embodiment of the present invention.

FIG. 9 is a sectional view of the track link shown in FIG. 8 taken along the line IXIX.

FIG. 10 is a side view of a portion ofa track link illustrating still another embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1,- a track chain assembly for a crawler vehicle is shown generally at 10 in driven engagement with a sprocket 11, having teeth 12, which is mounted on a vehicle (not shown). The track chain comprises a plurality of track links 13 and 13a hingedly joined together by track pins 14.

The track links have shoes 15 mounted on one edge thereof, and have rails 16 formed in an opposite edge which are adapted for engagement with track rollers mounted on the vehicle suspension (not shown).

Referring to FIG. 2., each track link 13 has bores 17 provided in ends 18 and 19 of the link and has ends I8 and 19 disposed on pins I4 alternately inboard and outboard of the adjacent ends of adjacent links. For each track link 13 there is a corresponding track link 13a having its respective ends disposed on the same pins as the respective ends of track link 13 but separated therefrom at the ends disposed inboard of adjacent link ends by bushings 20 also disposed on pins 14.

Bushings 20 are engaged by sprocket teeth 12 shown in phantom in FIG. 2 as the track chain moves around sprocket lll. Each sprocket tooth 112 exerts a force F on the bushing and pin which is resisted by track links 13 and 13a through their inboard ends 18 and 18a which are disposed on pin I4. Thus the reaction forces of track links l3 and 13a on pin 14 are immediately adjacent the area of contact of tooth 12 on bushing 20 and pin 14. Accordingly, bending moments in pin 14 are minimized. Such a track chain construction without a removable rail wear plate is shown in US. Pat. No. 3,492,054.

The prior art arrangement is shown in FIG. 3 where the ends of the track links resisting the force exerted on pin 14' are located at the extreme ends of the pin, which maximizes the bending moments in pin 14. To support thepin against such bending moments an extended bushing 19' is provided which extends through a large bore 22 in the inboard ends of the adjacent track links. Referring to FIG. 4, this large bore in the inboard ends of the track links results in track links having a profile height D at their inboard ends. If a portion of such links were to comprise a removable rail wear plate, the overall track link height D would not allow both the removable rail portion and the remaining track link portion to be of sufficient thickness to withstand the forces imposed thereon.

Referring now to FIG. 5, in the present invention, the bores in the track links are the same on each end of the links, resulting in an overall track link profile height D, which allows for a removable rail wear plate of sufficient thickness for adequate strength, while maintaining a track link of sufficient thickness to withstand the forces imposed thereon.

Referring now to FIG. 6, track link 13 constructed in accordance with the present invention has a bore 17 in each end thereof and has a removable rail 24 secured to one edge 26 by weldments 28 and 30. It has been found that repeated pounding of the'rails by track rollers causes the rails to grow longitudinally. To allow for such rail growth without imposing shear stresses on the juncture of the track link and the rail, the rail is welded to the track link only along its central portion and at the extreme ends of the rail. Cross bores 32 in the rail and in the track link form thin extended portions 34 of the rail which are softened by heat from the adjacent welds 30. Thus thin portions 34 relieve shear stresses in weldments 30 as the rail grows.

Referring to FIG. 7, the central portion of the rail is provided with a longitudinal groove 35 to allow easy removal of the rail with a cutting torch. Cross bores 36 at the ends of groove 35 also promote easy removal of the rail and avoid stress risers at the ends of groove 35.

Referring to FIGS. 8 & 9, alternative means of attaching a rail 24' to a link 13 may be by bolts 37 extending through track link 13 and screwed into tapped holes 38 provided in the rail. To restrain rail 24 laterally with respect to link 13, an edge surface 26' on the track link adapted for engagement with the rail has keys 40 provided thereon which mate with grooves 41 provided in rail 24. Keys 40 and grooves 41 run longitudinally along the track link and rail and allow the rail to move longitudinally with respect to the track link,

but restrain it laterally. Bolts 37 secured to the central portion of the rail serve to restrain the central portion of the rail longitudinally with respect to the track link, and as a result restrain the entire rail longitudinally with respect to the track link except for growth in the rail that may take place.

As shown in FIG. bolts 42 may also be secured to the rail by friction welds 43 and extend down through the track link and track shoe 44 which are secured thereto by a nut 45.

I claim:

1. A link assembly for an endless chain comprising:

a longitudinal link an edge surface provided on the link,

a replaceable rail having a central portion, and end portions on either side of the central portion in abutting engagement with said edge surface,

securing means rigidly securing said replaceable rail to said link at the central portion of the rail and at the ends of the rail and stress relieving groove means located adjacent at least one of said securing means for allowing longitudinal growth in the central portion of the rail without proportional stressing of the securing means.

2. The combination of claim 1 wherein said securing means comprises,

central weldments securing the central portion of the rail to the link, and

end weldments securing the extreme ends of the rail to the link,

and wherein the stress relieving means comprises,

transverse groove means provided in said rail adjacent said end weldments forming a relatively thin portion in each end of the rail whereby any shear stress in the end weldments resulting from longitudinal growth of the rail will be relieved by strain in the thin portions of the rail.

3. The combination of claim 2 further comprising a longitudinal groove in the central portion of the rail adjacent the central weldments whereby the central weldments may be easily destroyed with a cutting torch.

4. The combination of claim 3 further comprising transverse grooves in the rail at each end of the longitudinal groove.

5. The combination of claim 1 wherein said longitudinal link includes means forming a pin bore of equal size in each end of the link for receiving respective pins of the endless chain whereby the ends of the link are equal in thickness and strength. 

1. A link assembly for an endless chain comprising: a longitudinal link an edge surface provided on the link, a replaceable rail having a central portion, and end portions on either side of the central portion in abutting engagement with said edge surface, securing means rigidly securing said replaceable rail to said link at the central portion of the rail and at the ends of the rail and stress relieving groove means located adjacent at least one of said securing means for allowing longitudinal growth in the central portion of the rail without proportional stressing of the securing means.
 2. The combination of claim 1 wherein said securing means comprises, central weldments securing the central portion of the rail to the link, and end weldments securing the extreme ends of the rail to the link, and wherein the stress relieving means comprises, transverse groove means provided in said rail adjacent said end weldments forming a relatively thin portion in each end of the rail whereby any shear stress in the end weldments resulting from longitudinal growth of the rail will be relieved by strain in the thin portions of the rail.
 3. The combination of claim 2 further comprising a longitudinal groove in the central portion of the rail adjacent the central weldments whereby the central weldments may be easily destroyed with a cutting torch.
 4. The combination of claim 3 further comprising transverse grooves in the rail at each end of the longitudinal groove.
 5. The combination of claim 1 wherein said longitudinal link includes means forming a pin bore of equal size in each end of the link for receiving respective pins of the endless chain whereby the ends of the link are equal in thickness and strength. 